Also known as folding noise, aliasing error
In digital signal processing, aliasing is a phenomenon that a reconstructed signal from samples of the original signal contains low frequency components that are not present in the original one. This is caused when, in the original signal, there are components at frequency exceeding a certain frequency called Nyquist frequency, f_s / 2, where f_s is the sampling frequency (undersampling). This is because typical reconstruction methods use low frequency components while there are a number of frequency components, called aliases, which sampling result in the identical sample. It also often refer
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- Commons category
- Aliasing
- Stack Exchange tag
- stackoverflow.com/tags/aliasing
- different from
- aliasing
- maintained by WikiProject
- WikiProject Mathematics
- has cause
- sampling
- handled, mitigated, or managed by
- filtre anticrénelage
- opposite of
- anti-aliasing
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Article · 中文
混疊（英語：Aliasing），在訊號頻譜上可稱作疊頻；在影像上可稱作疊影，主要來自於對連續時間訊號作取樣以數位化時，取樣頻率低於兩倍奈奎斯特頻率。 在統計、訊號處理和相關領域中，混疊是指取樣訊號被還原成連續訊號時產生彼此交疊而失真的現象。當混疊發生時，原始訊號無法從取樣訊號還原。而混疊可能發生在時域上，稱做，或是發生在頻域上，被稱作。 在視覺影像的類比數位轉換或領域，混疊都是相當重要的議題。因為在做類比-數位轉換時若取樣頻率選取不當將造成高頻訊號和低頻訊號混疊在一起，因此無法完美地重建出原始的訊號。為了避免此情形發生，取樣前必須先做濾波的動作。
Abstract from DBpedia / Wikipedia · CC BY-SA